Radiation damage is known to have a severe, destructive effect on biological specimens when they are brought into the beam of the electron microscope. The goal of this research project is to obtain experimental data on the rate at which this damage is produced at different acceiating energies, particularly for energies above 1 MeV. The 3 MeV electron microscopes at Toulouse and at Osaka will be used in this research, and various electron linear accelerators will be used, when feasible. Radiation damage will be monitored in terms of loss of crystalline structure. This can be done by recording the electron diffraction pattern produced by the specimen. For more radiation resistant materials one can also observe the degradation of the direct latttice images. It is hoped that more can be learned about the mechanism of radiation damage from the direct lattice studies. Theoretical and experimental work will also be undertaken to investigate the improvement in contrast for imaging of heavy atom labels in organic specimens. A large improvement in contrast would lead to a corresponding decrease in the exposure time required to obtain a satisfactory image, and thus a decrease in the amount of radiation damage.